Next-Generation Sustainable Lightweight Fatigue-Critical Components Research

二十年来，交通运输车辆结构发生了革命性的变化，为了解决更好的燃油经济性的需求，车辆轻量化。尽管在结构部件中引入铝合金取得了进展，但轻量化的尝试仍然达不到严格的燃油效率目标。为了最大限度地利用轻质材料在车身结构中的使用，最近出现了一种多材料轻量化汽车结构的概念。这一概念要求使用最轻的材料，在所使用的位置具有最佳的性能。*镁合金比钢轻75%，比铝轻35%，表现出优异的疲劳性能，使其成为疲劳关键部件的可行替代品，这些部件是以疲劳强度为关键性能指标的部件，如汽车的发动机底座或飞机的机翼-机身连接凸耳。与目前用于类似部件的A356或AA6082等铝合金相比，ZK60等镁合金的疲劳性能优于铝。然而，目前的文献在解决镁合金这种应用的可行性方面存在着重大的科学空白。拟议研究的目标是开发知识库，并使镁合金应用于运输车辆疲劳关键部件的技术成为可能，最终目标是设计下一代可持续的轻量化部件。*由于其优异的比强度，变形镁合金是更好的承重部件。然而，除了HCP微结构继承的屈服不对称性外，它们还表现出由制造过程中涉及的严重塑性变形引起的方向各向异性。本研究将对新开发的变形镁合金在多轴疲劳载荷下不同方向的循环行为进行研究，并建立相应的设计模型。*这项拟议的研究是第一次检验最轻的结构金属是否适合制造下一代疲劳关键部件。从铸铁冲压到钢冲压，以及从钢冲压到铝合金的过渡都需要近20年的时间。预计从目前的铝合金向下一代轻质铝合金的过渡也将需要大约相同的时间。因此，拟议的研究的时机是正确的，以开发下一代部件所需的知识和使能技术，这些部件预计将在未来十年内上市，以按时实现目标燃油效率。由于运输车辆制造占加拿大贸易的30%，预计通过拟议的研究开发的创新将确保加拿大在未来市场上保持竞争力。

There has been a two decade-long revolutionary changes in transportation vehicle structure light-weighting to address the need for better fuel economy. Despite the progress made by introducing aluminum alloys into structural components, light-weighting attempts still fall short to meet the drastic fuel efficiency targets. To maximize the use of lightweight materials in the vehicle body structure, a recent concept of multi-material lightweight vehicle architecture has emerged. This concept calls for the use of the lightest material with the best performance in the location used. ***Being 75% lighter than steel and 35% lighter than aluminum, magnesium alloys have shown an excellent fatigue performance that nominates them as a viable replacement for fatigue-critical components, components with fatigue strength as their key performance indicator like the engine cradle in a car, or the wing-fuselage attachment lugs in airplanes. When compared to aluminum alloys like A356 or AA6082 currently employed in similar components, magnesium alloys like ZK60 outperform aluminum fatigue behavior. However, there is a major scientific gap in the current literature in addressing the feasibility of such applications for magnesium alloys. The objective of the proposed research is to develop knowledge base, and enabling technologies for the application of magnesium alloys to fatigue-critical parts of transportation vehicles with the ultimate goal of designing next-generation sustainable lightweight components. ***Due to their superior specific strength, wrought magnesium alloys are better candidates for load-bearing components. However, beside the yield asymmetry inherited by HCP micro structure, they show directional anisotropy induced by the severe plastic deformation involved in their manufacturing process. The cyclic behavior of newly developed wrought magnesium alloys in different directions under multi-axial fatigue loading will be studied and the enabling design models will be developed in this research. ***The proposed research is a first of its kind in examining the suitability of the lightest structural metal for next-generation fatigue-critical components. The transition from cast iron to steel stamping; and steel stamping to aluminum alloys each required nearly two decades. It is expected that the transition from current aluminum alloys to next-generation lightweight counterparts will also require about the same time. Therefore, the proposed research is right in timing to develop the knowledge and enabling technologies required for the next-generation components that are expected to become market-ready in the next decade to address the targeted fuel efficiency on time. With transportation vehicle manufacturing accounting for 30% of Canada's trade it is expected that the innovation developed through the proposed research ensure that Canada remains competitive in the future market.